Elastic fluid turbine



Aug 27, 11935. B. POCHOBRADSKY ELASTIC FLUID TURBINE Filed Nov. 11 1932 2 Sheets-Sheet l d m/L N a m A m) m 5/,

Aug, 27,, 1 935. B. PQCHOBRADSKY p p ELASTIC FLUID TURBINE Filed Nov. 11, 1932 2 Sheets-Sheet 2 Patented Aug. 27, 1935 UNITED STATES PATENT OFFICE ELASTIC FLUID TURBINE London, England Application November 11, 1932, Serial No. 642,228 In Great- Britain November 26', I931 16 Claims.

This invention relates to the governing of prime movers, oneobject of the invention. being to provide an improved form of governing which may be. applied to electrically driven ships. Further objects of the invention will become apparent from the specification.

Where elastic fluid turbines are required to operate over a large range of speed, as is the case with turbines for ship propulsion, difiicultiesarise in the governing; the turbine should run steadily at any speed within itsrange of Operation, but at slow speeds, the quantity of. steam required to drivethe turbine is small, and the control of such. small quantities of steam, especially at high pressure, is liable to be unsatisfactory with the methods known at present, both on account of the difficu-lty of controlling the flowof steam and of so arranging the governor that it shall operate satisfactorily over a wide range of speed. Prior known ship propulsion systems wherein elastic fluid turbines drive the ship through electrical generators and motors are known to utilize controllers for the generators and motors, the controllers being geared to mechanism actuating the throttle valves of the turbines and the controller and throttle valve are adjusted by the same hand wheel; but such control is not satisfactory in that the range of control is limited since there is no control of the governor which controls normal: operation of the turbine. For this reason there isa difiioulty in ensuring that,

in electrically driven vessels, the operation oi the electrical gear is properly eo-ordinated with that of the governor. Among. other objects, the inventionis intended to overcome these difficulties. In one system oi electrical ship propulsion in accordance with the invention, there is provided a prime mover, at least one electrical generator driven by said prime mover, at least one electrical motor deriving current from the said generator, and electrical gear is provided for regulating the 9 operation of the motor, while there is a speed responsive governor for the prime mover, means for regulating the normal speed of the governor,

45 and the latter means is interlocked with the electrical control gear. It is thus ensured that the operation of the electrical gear is properly co-ordinate'd' with the operation of the governor.

In addition to the governor referred to above,

50 an additional speed responsive meansmay be provided to limit the speed of the prime mover to a desired value below the maximum permissible speed. This latter speed responsive meansmay bein the form of a constant speed governor,-

55 although it may be simply a speed limiting device: where a. constant speed governor is provided. for this purpose, it may be arranged tobe inoperative at normal speeds and to come. into operation. only when the highest normal working speed has beenexceededthe highest nor 3 mal working speed being the speed at which the prime mover runs when the vessel is proceeding at full speed under normal conditions.

The main speed responsive governor may take the form of an hydraulic pump drivenby the 10. prime mover, working in conjunction with a device responsive to the pressure generated by the said pump, this latter device being. arranged to control the running of the prime mover; and the meansfor regulating the speed at which. the 5, governor tends to run may consist of a valve mechanism adapted to vary the relation between the speed of the pump and: the pressure produced by the pump: at that speed. Where the prime mover drives a plurality of generators,. 20. or supplies a plurality oi electrical motors, meansmay be provided to vary the setting of the said. valve mechanism in dependence upon the num ber of generators (or motors, as the case may be) in circuit.

Where the prime mover is a steam turbine, there is, as referred to above,. a difficulty in controlling the steam supply when the flow is small;- and this difiiculty may be overcome by arranging that the steam is throttled twice, when the flow 3D is small, by passing it through two throttle valves in succession.

Arrangements accordance with the inventionwill now be described by way ofexample with reference to the accompanying drawings, 35 in which Figures 1 and 2 show diagrammaticah ly a governor arrangement for a turbo-electric ship drive, and Figure 3 is a section viewed in the direction: of. the arrow LIL-11]; through the control valve used in the arrangement shown in 40 Figure 1, while Figure 4 shows a diagram of the operation. of the throttle valves shown in Figure 2.

As shown in: Figure 1, the turbine (not shown) drives a pump l which sucks a suitable liquid (generally oil) from tank: 2 and delivers it through pipes 3 and t to the control valve 5 andto the underside of the spring-loaded piston 6; The motion or this: piston controls through suitable mechanism the quantity of working fluid passing to the prime mover (as is described in detail below) the piston G controlling the admission or steam to-the turbine in such a way that the steam. admission va-Ivecloseswhen the piston 6- rises.- Inorder to prevent the speed or the prime mover excontrolled solely by the piston 6. If the highest" speed of the working range is exceeded th'e-governor 8 begins to move the point Ta upwards, thus restricting the admission oi steam"to the'; prinie1 15 mover, as is further described belowl The control valve 5 consists of three concentric sleeves 9, I and H; the inner sleevej9 can' be, rotated by means of gearing l2"'and a control wheel l3. It is provided with a port (H extending 20 over a part of its periphery, for example half its periphery sis-illustrated. The'intermediate' sleeve I0 is stationary, bein'g attached-to the housing" l; itis provided with openings of suitable areas such as the twoports 'lii and l'l 'sliown'in-Figure 3: the Q5 outer sleeve ll is provided witha port l8, and it can be turn'ed-by means of asolenoid Qthrough element: levers as shown-Z- In Figure'3, the control-velvet is shown in a position 'whenthe open-valvgar ea is a maximum. 31; By'turning'the sleeve 9 counterclockwise through 180ftheports-wil1-be' covered and "the valve is closed: lByturnin'g the sleeves frorri this -closed position in a clockwise direction through about 45 the" port I6 is uncovered, and a further-turn 35 through 45"--still leaves port l6 alone uncovered, the open valve area remaining constant during this "second turn 0f-45-.- A further rotation of thesleev' through 90- gradually uncovers the-port Il irf'addition to the port-16: while, fina'llyfthe g: valve position illustrated in; Figure 3 being reached, the control valve '5 is full open. The handwheell3'also cohtrolsyby means of gearingliiif'the electrical control gear ear the generators and motors deriving power from the prime mover;

5! This control gear is represented diagrammatically The-"governor arrangement just' described is suitable for the control of a turbine which drives a-plurality of generators, or -a single generator 3 supplying a plurality-of electric motors} The solenoid i9 is arranged to be energized if a generator, or a motor, as the case may be,-is cut out of service, and when energized, the solenoid l9'rotates-the sleeve I l in a' counterclockwise direction 55 (as viewed in Figure 3), partially closing port lland thus reducing the opening of the valve 5;

- The piston 6 is connectedasaforesaid, to the floating link-1, which is in turn'connected by the link 22 and the lever 23 (which is pivoted on brackeet 24) and the link25 to the floating lever 2601? the pilot valve 21, (Figure 2) the'en'd of the lever 26 which is remote from valve 21 being connectedlin known manner) to valve spindle 28, which carries the turbine "throttle valve 29 at its lower end and E at its: upper end carries power pist0n 30 which.

worksin cylinder 3"I'and is'loaded byspring 32.

Valve21 works'in asleeve'33 provided with an inlet port 34for-oi1 under pressure, and an outlet- ,po'rt 35 communicating through passage 36 with 5 the=underside of piston30.

known, provides a fol- This mechanism, as is low-up arrangement by which the position of the It will be seen that, if piston 6 falls owing to a decrease in the speed of the turbine or to the opening of valve 5, (so that there is a call for a supply of steam to the turbine), the end 23a of lever 23 rises and raises floating lever 26, 5 thus raising valve 21 and opening port 35. This permits oil to flow .frominlet 34 through passage as to the underside, of piston; 30, tperebyilaisin it. As piston 30 rises, it'ope'ns valve 29, thereby al l owing more steam to flow from the inlet 85 to the branch 86 which is connected to the turbine. The -ris'ein the piston 39 also has the eifect of raisingspindle 28 and with it the end 26a of ,i yer'j za q "that va ve" 2'! is once more lowered until it closes port35. If, on the contrary, the turbine speed rises or valve 5 is closed, piston 5 j rises leve r 25 iallsy-thus lowering valve 21, and

connection is es't'ablished between passage 36 and they open upper end 39 of sleeve 33, through the open port 35, so that oil can flow from under piston '30, through passage 36 -and 'p01t "8 5 to chamber 40 and oildrain 4 I :"Pistontfi then falls; closing valve 2 9 somewhat, and at the same time raising-valve21-untilf'port 3 5 is once rnor'e-closedand themove'm'ent cea'se's. f It will be noted that'an oil'drain and airrelease 42 isprovidedirom the top"of cylinder"'3l to chamber '40," a'n'd'f'a "similar onnec'tion 43 "is provided from i the top ofeyiia'ar =4 d' -(Figumf 1) in"which work's piston '55" In addition, anadjust A ing wheel =45 is provided 011' cylinder 44 that the compressionoffspring 2B may be varied, thus regulating the oil -pressure'reduired to' lift piston 6 a'ndhence' adjusting the turbine speed."

Asreferred to above, a g'overnor 8 is provided 35 to take charge ot-the' turbine onoverspeed. It' will be seen that whe'n the speed increa ses suifi ciently to cause the bob-weights @6110 move out"- wards, thespindla l'l is retracted,--raising link 22'=and lowering 11m; 25"a'nd-valve 21; A es;- 49 plai'ned above, this causeswalve 29 to be closed somewhat, thuspreventing excessive overspeed' me. The operating- 'oftheihterlocking part'of the' new governing gear will now be' described in de' 45 tail, the description of the mode of operation of the throttle valves being described later." -The speed of the pump I, driven by the prime-- mover, will be'in constant 'ratioto the'speed'of the-prime-moven- In increasing the speed of the 5G prime mover' and consequently of the pump the output of-the pump will in'cr'ease',and if a gear type of pump is used the quantity of liquid de-' livered will increase'directly'as the speed (approximately). If'the open area of the-control 51 valve 5 is varied in the same degree as the speed, the pressure in the pipes 3 and 4 and underneath the piston 6 will remain practically unchanged, the piston Bremaining substantially-in the same position. Assume the control valve 5 closed; for a certain lowestjspeed the'pump' l'will deliver a quantity just sufiicient to supply the leakage in the control valve 5 and around the piston 6, jthe pressure being just sufficient to lift the piston 6' to its maximum height, which practically closes the organs for the admission of the working fluid to the prime-mover. By rotating the wheel l3; through a small angle, (and with'it thesIeeVe 9) thus opening slightly the control valve, more. liquid will pass through this valve and drain to the a 2 so th t; the pressure in the pipes 3; and 4 and underneath the piston 6 will fall slight-. ly; the piston 6 willthen move downwards alittle and increase the admission of working fluid-to the prime-mover,- the speed; of the latterbeing increased:

further increasingi the-i-open'iarea ofv the valve dithespeed'of the-primeamover'willbe fur- .5 ther increased. :Jissumeithatv load is now. put on the primemover'whil'e' itsis. at a given speed. Thisloading slow down .the primemoyer, the-pump liwill deliver-less-liquidthe pres.- smre underneath :the-piston twill fall 'the piston 1 lsmiltsmovesdowhwards and sodncreasetheadmissimof-workingflnidto the prime-mover. Thespringfltflvhichrtendstozthrust .the piston. 6 to itsilowiest; position; iSsmdimenSiQned that; when full load is thrown on the primeemovercwhen 151 it is running at its normal speed, the speedreductionrisa-withhirsay 5%;- iiThis. speed; reduction is: snflicientiior- -..the pressure-underneath the pis-,

hams q.to-..fah-itthe.open;.area oi theyalve 5--re.-. main'ing; unaltered-)2. :to its; lowest position, :the 2m; admission of the: workingfluidto the prime-mov increased-to its ,It .is. clear that tor.- a.-.definite open area; of -the-,,valve 5- the speed Ofizthfl prime-mover .will .be maintained constantiwithina iewpercent withtheload varying 2dnwiiihirrtheiulliranger= a 1r In order .to. providethe interlockingoithe turhine=controlawith theelectrical, control gear, the

handwheel; t31is conneciedszasareterred tq-above When.starting.-.up,. the prime-mover with its electric alternator. is run up to some-low speed at.

which; ithe; pumpv I: delivers a, quantity of liquid (withfithe control valveSin closed? position) which may be. say 56 of. fullspeed, the electrical switch gearbeing in the. pen- .;position. The controls of direction is now set forehead or astern going. as desired... .By; turning the handwheel I3 50 through ,lfiOithe ,dirwtionvcontaotcrsgof the propulsion. motors-are closed, theport 16 of the valve is.;,gnaduaallyz-,opened the speed oflthe ,primemover. ir1;creasing, ,to say 1 of full speed, the altenat-orfields are over-excited; and the propulsion 55L motors are-broughtupytoaspeed corresponding -'-tothee-actual. speed =of the prime-mover. By

the handwheel- 'l jll; througlnanother. 99,

the actuation of. the controller 2i causes the motor fields. tobeccn e, excited-,and themotors to 60 pull; into-psynchrenism. the sleeve: 9.,02 control 'valvefi, meanwhile turning throughanother 22 which-,dPeS:nqt-open.any additional port so that theQspeed-Ioithe primemoverand alernator remainsunadeclted... Byturning the handwheel i3 through a further 907,. the open area of valve 5 remains, unaltered; and the alternator fields are reduced to normal. The handwheel l3 may now bev turnedbys any fraction of anadditional complete turnin the same direction. as before, the 1 7Q sleeve 9.-of. the valvedaccordingly turning withinthezadditional. angle 90, and the port I! being mone..ou,less;uncovere.d. so, that the speed of the prime-mover: ismore or .less increased accordingly,,, the highest. speed. being- ,cbtained when the 7 56 contr.ol wheel, lt has periormed two full turns.

suflicient, tocontrol the-speedof the prime-mover,

By, turning the. handwheel it in the opposite direction from this extreme position through two full turns, the plant is brought into the original condition which existed at starting up, just before the handwheel i3 was moved from its zero position.

The arrangement wd control of the throttle valves .for the turbine will now be described;

. It will besecn from Figure 2, the piston 30' car'- i'ies a link'fili connected to a bell crank 49 pivoted at 56 in thecap iii of cylinder 3!. The bell crank i9is connected by links 52 and 53 with bell cranks fili-andfifipivoted at 55 and 5?, respectively, in. the caps 58 and 53' cfadditional power cylinders 60' and 6!. ..-Bell crank 54 is connected by link 62' to the pilot valve 83 for piston 64 whichis in turn connected'by valve spindle 5 to throttle valve 66-.

The pilot valve '33 works in a sleeve 61 which is mountedon the end of spindle 55 and is provided .vrith oil inlet passages 88 and oil outlet ports 59-. 'Thc piston 54 is biased towards the bottom of cylinder 68 by spring 76.

- The arrangement for the control of the relay cylinder 6i and associated gear is similar. Bell crank 5 is connected by link H to the pilot valve 72 for pis on 73, which is in turn connected byvaive, spindie- 74 to throttle valve 35. The pilot valve '72 works in a sleeve 73 which is mounted. on theupperend of spindle l4 and is provided with 'oil inlet passages ii and outlet ports 18.- The piston is biased towards the bottom of cyl nder 6! by spring '19.

- With this arrangement of throttle valves, if pilot vaive is raised so that communication is established between oil inlet 3 port 35. passage 35 and the mideiside of piston 39, causing it to rise (as described above), the rising of piston 30 raises link :28, and causes bell cranks 59, 54 and 55 to turn in a counter-clockwise direction as viewed in Figure 2. Tins raises pilot valve '12 and its head "#28. uncovers port l8, so that communication is established between pressure oil inlet 86, chamber 8!, pas ages '13, port 8 and the Lmderside of piston 13. The pistons 39 and 13- accordingly rise together and throttle valves 29 andili open simultaneously, piston '58 rising until its motion causes ports 18 to become closed once more.

The valves 29 and 15 being lifted off their respective seats 82 and 83, steam fiows from inlet 84-through valve 15 into valve chest 85 and then through valve 29 to the outlet branch 86 whence it passes to the turbine. It will be seen that the steam flowing to the turbine is thus twice throttled, and this permits the flow of small quantities of steam-to be regulated accurately and with certainty, which is very desirable for the satisfactory control at low loads of marine turbines for electric propulsion. As the valves are lifted further and further from their seats the steam flow increases, double throttling is, however, no-longer necessary, and for this reason. the arm 59;; of hell crank 49 is made longer than the arm 558L or" bell crank 55, so that pilot valve 12 rises more rapidly than does piston 30: accordingly. valve l5 opens more rapidly than valve 29, and the throttling effect it exerts on the steam also decreases more rapidly, until, when the steam flow is of such amount that it can conveniently be controlled by a single valve, valve 75 has reached the full open position (i. e. the position at which further opening produces no appreciable increase in steam flow), the whole of the control being exerted by valve 29.

Ifthe piston-Sll-ccnin'nues to: rise after valve 15 has reached the full open position, the pilot valve 63 is raised further and further until its head 63a covers ports 69 just as valve 29 reaches its full open position. (It will be understood that the valves 29 and 15 and their seatings 82 and 83 must be given a suitable conformation, the method of designing such valves being well-known in the art). If now, further load be put on the turbine, or control valve 5 is opened further, pilot valve 27 again admits oil to cylinder 3|, raising piston 30 and with it pilot valve 63, and the head 63:]. now uncovers ports 69, establishing communication between pressure oil inlet 81, chamber 88, passages 68, ports 69 and the underside of piston 64. The latter accordingly rises, opening valve 66, and admitting steam fram valve chest 85 to the outlet 89 connected to the overload nozzles of the turbine.

If the speed of the turbine rises, or the control valve 5 is closed, the reverse series of operations is performed. Valve 63 is lowered, permitting oil to flow from the underside of piston 64 through ports 69 and the open upper end of sleeve 61 to the upper part of cylinder 60 and thus to drain 9B. A similar drain 9! is provided on cylinder 6!.

The mode of operation of the governor is illustrated graphically in Figure 4, in which the lines marked Valve 29, Valve 66 indicate the proportion of their total areas which each of the valves presents for the passage of steam for various positions of the lever 26 (the amount by which the point 26b has moved away from the position which it assumes when all the valves are closed,

- is referred to in Figure 4 as the governing lift).

It will be seen that since the valve i5 rises from its seat more rapidly than does the valve 29, as point 26b moves away from the closed position-Which is the position shown in Figure 2- valve reaches its full open position before valve 29 does so; and, as explained above, the rates of lift are so adjusted that valve 15 reaches its full open position (indicated by point a in Figure 4) at a time when the quantity of steam passing the valves is large enough to be properly controlled by valve 29 alone. Similarly, when valve 29 has reached its full open position b (in Figure 4, valve 66 starts to open.

It will be understood that more than one overload valve such as 66 may be employed, and that the valve 66, and any other overload valves, may receive steam direct from the steam main, instead of receiving steam that has already passed through a throttle valve such as 15.

Moreover, the rates of opening of valves 29 and 15 may be made the same, so that both perform a throttling action over the same range: the important point in regard to this double valve arrangement, is that both valves should produce a throttling action over that part of the range in which the steam flow is too small to be regulated with suflicient accuracy by a single valve.

It will also be appreciated that the interlocked control and governing arrangement, as shown in Figures 1 and 2 may readily be adapted for the control of an internal combustion engine. The link 25 would, in this case, instead of being connected to the floating lever 28 of the relay gear, be connected to the organ controlling the supply of fuel to the engine; for example, it might regulate in known manner the operation of the fuel injection valve of a Diesel engine.

By the use of the interlocked governor in accordance with the present invention. the control ,of an electrically propelled vessel may be greatly prime-mover when an electric generatoronm'otoris cut out of operation, this speedlimit beingsuch as to prevent the remaining electrical machinesbeing overloaded.

I claim:- 1. In an elastic fluid turbine installation, adapted to work over a large range of quantities of elastic fluid, an elastic fluid turbine," .13, load driven by said turbine, an hydraulic pump .driven by said turbine, a pressure-sensitive device com prising a cylinder and a spring-loaded piston therein subject tothe pressure of the fluid delivered by said pump, manually operated valve means for regulating the pressure on said piston by controlling the escape of fluid-between said pump and said piston, means operating in dependence on the position of the piston in said cylinder for regulating the flow of elastic fluid. into the turbine and a control member' inde-' the extent to means for controlling-the pressure transmittedby said fluid to said piston, a control member independently operable for controlling the extent to which said valve is opened, at least one throttle valve for controlling the supply of elastic fluid 'to' said turbine and an hydraulic relay for operating said throttle valve and regulating the position in dependence upon the position of said piston.

3. In an elastic fluid turbine installation adapted to work over a large range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, an hydraulic pump driven by said turbine, a pressure-sensitive device comprising a cylinder and a spring-loaded piston therein subject to the pressure of the fluid delivered by said pump, manually operated valve means for controlling the pressure transmitted by said pump through said fluid to said piston, a control member independently operable for controlling the extent to which said valve is opened, at least two throttle valves through which the elastic fluid supplied to said turbine passes in succession, and relay means controlled by said pressure-sensitive device for regulating the positions of the respective throttle valves in dependence upon the position of said piston.

4. In an elastic fluid turbine installation adapted to operate over a large range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, an hydraulic pump driven by said turbine, regulating means for said turbine comprising a pressure-sensitive device operated by fluid from said pump, and valve means for regulating the speed-pressure char acteristic of said pump comprising a control va-lve having at least two concentric sleeves provided with suitable openings, manually operable means ifor controlling-the movement of. one of said sleeves and independently operable meansior moving another of said sleeves for controlling the passage of the elasticfluid to the turbine, the elastic fluidlpassing -through said valves in succession, means operatedby saidgovernor for controlling operation of said throttle valves in prearranged sequence and control means for adjusting the operating range of said governor to thereby regulate the normal speed of the turbine within the range selected.

6. In an elastic fluid turbine installation adapted to work over a wide range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a plurality of throttle valves, a fluid pressure pump driven by said turbine, control means, for regulating the effective pressure delivered by said pump, speed governing means responsive to the eflective pressure delivered by said pump and means controlled by said overning means for operating at least two of said throttle valves through which the elastic fluid for operating the turbine is required to pass in succession.

'7. In an elastic fluid turbine installation adapted to work over a wide range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a fluid pressure pump driven by said turbine, a fluid pressure sensitive device comprising a cylinder and a spring-loaded piston therein arranged to control the speed of the turbine according to the eflective fluid pressure delivered by said pump, control means for varying the effective pressure on said piston by controlling the escape of fluid between said pump and said piston, at least two throttle valves through which the elastic fluid for operating the turbine is required to pass in succession and pilot valve operated means controlled by said pressure sensitive piston for controlling operation of the respective throttle valves according to the speed of the turbine.

8. In an elastic fluid turbine installation adapted to work over a wide range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a fluid pressure pump driven by the turbine, a pressure-sensitive device subject to the pressure of the fluid delivered by said pump, control valve means for controlling the fluid pressure transmitted to said pressure-sensitive device, at least two throttle valves through which the elastic fluid for operating the turbine is required to pass in succession, means controlled by said pressure-sensitive device to cause one of said throttle valves to open in dependence upon the pressure transmitted to said sensitive device, and means controlled by the opening of the first throttle valve to cause the opening of another of said throttle valves.

9. In an elastic fluid turbine installation, adapted to work over a large range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a fluid pressure pump driven by said turbine, control means for regulating the effective fluid pressure of said pump, means responsive to the effective fluid pressure delivered by said pump and arranged to be regulated by sa d last named means, a plurality of throttle valves controlling admission of elastic fluid to the turbine and means. operatively ;connected with saidapressureeresponsive means for-operatiing said; throttle valves in succession; for control ling said 'turbine,'one of said ithrottleivalves being brought :into' operation only upon overloadr'of the I turbine. 10.. In an. elastic fluidfJturbinexinstallation, adapted-to work overa: wide range of quantities of'elastic fluid: an-elastlc fluid 'tu1'bme, ."a.='rload drivenv by said turbine; a fluid-pre'ssure zpump 'drivenzby said'turbine, a control lvalve-rforiregw iaising the 1 effective fluid pressure delivered' :said'puinp, a plina'lity of throttle valves for reg:- ulatlng =theaflow of elastic fluid to' sai'd turbine, means comprising a pressure-sensitive device responsive to the eflfective fluid pressure from said pump, as determined by said control valve, for operating at least two of said throttle valves substantially simultaneously, said two valves being so arranged that elastic fluid to the turbine is required to pass through them in succession, and means controlled by said pressure-sensitive device for opening a, third throttle valve upon overload of the turbine.

11. In an elastic fluid turbine installation, adapted to Work over a large range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a. fluid pressure pump driven by said turbine, a pressure-sensitive device comprising a cylinder and a spring-loaded piston therein subject to the pressure of the fluid delivered by said pump, a control valve for controlling the eflective fluid pressure on said piston, a plurality of throttle valves at least one of which is arranged for controlling the supply of elastic fluid to said turbine under normal operating conditions, pilot valve operating means for said normal operating throttle valve arranged to regulate the position thereof in dependence upon the position of said piston, and means controlled by said normal operating throttle valve for bringing into operation another of said throttle valves upon overload of the turbine.

12. In an elastic fluid turbine installation in accordance with claim 8, an auxiliary constant speed governor set to take control of the speed of the turbine only when and if the speed of the turbine exceeds a prearranged highest normal working speed by a determinate amount and means brought into action by said auxiliary governor for operating said throttle valves to prevent the speed of the turbine exceeding the prearranged highest value.

13. In an elastic fluid turbine installation in accordance with claim 8, an auxiliary constantspeed governor connected and arranged to control operation of said plurality of throttle valves only when and if the speed of the turbine should exceed its normal speed while under control of said pressure sensitive device by a determinate amount and means brought into action through operation of said governor to prevent the speed from rising to a higher value.

14. In an elastic fluid turbine installation adapted to work over a large range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a fluid pressure pump driven by said turbine, a pressure-sensitive device comprising a cylinder and a spring-loaded piston therein subject to pressure of the fluid delivered by said pump, a rotatable control valve for regulating the effective fluid pressure on said piston by controlling the escape of fluid between the pump and said piston, at least one throttle valve for controlling the supply of elastic fluid to the turbine, means controlled by said pressure-sensitive device for regulating the position of said throttle valve in dependence upon the position of the piston in said cylinder, a control hand wheel for the turbine and gearing between said hand wheel and said control valve for rotating the latter to vary the fluid pressure on said piston.

15. In an elastic fluid turbine installation adapted to operate over a large range of quantities of elastic fluid, an elastic fluid turbine, a load driven by said turbine, a fluid pressure pump driven by said turbine, regulating means for said turbine comprising a pressure-sensitive device operated by fluid from said pump, a control valve having at least one rotatable member for regulating the speed-pressure characteristic of said pump relative to said pressure-sensitive device, a hand wheel for controlling the turbine and gearing connections between said hand wheel and said i rotatable member for rotating the latter to vary said speed-pressure characteristic.

16. In an elastic fluid turbine installation in accordance with claim 15, wherein said control valve is provided with another rotatable member 1 which is rotatable independently of said hand wheel to vary said speed-pressure characteristic.

BEDRICH POCHOBRADSKY. 

